cretaceous sponge fossil.

Darren came home from his post round today with something that he found whilst delivering about a mile inland. It was a round stone looking object that rattled when he shook it. He had thought at first it was a fossil of a sea urchin as he had found one a few weeks ago in the same general area but this was something different. He took it up to one of the local fossil experts who identified it as a cretaceous sponge fossil. He said he had seen them beofre but never ones that rattled. Darren brought it home and set about opening it, he was told that it wouldn't be a quick job and it really wasn't. Hats off to him as I probably would have ended up hitting it with a hammer!!! He however sat patintly using a mini grinding disc. When he broke through he called us over and we all watched as it opened and we saw together what no human had ever seen before. Jack was very excited and kept saying "wow, thanks Daddy".
I don't know much about this kind of thing but looked it up and this would be between 145.5 and 65.5 million years old. It was around with the likes of Tyrannosaurus rex and Triceratops. Amazing.